A conventional combustible gas turbine engine includes a compressor, a combustor, including a plurality of combustor units, and a turbine. The compressor compresses ambient air. The combustor units combine the compressed air with a fuel and ignite the mixture creating combustion products defining a working gas. The working gases are routed to the turbine inside a plurality of transition ducts. Within the turbine are a series of rows of stationary vanes and rotating blades. The rotating blades are coupled to a shaft and disc assembly. As the working gases expand through the turbine, the working gases cause the blades, and therefore the disc assembly, to rotate.
Each transition duct may comprise a generally tubular main body and a collar coupled to an exit of the main body. The transition ducts may be positioned adjacent to one another within a circular array. The transition duct collars connect to a turbine inlet. For optimal performance, preferably only combustion gases enter the turbine inlet. The ducts may include brush seals as shown, for example, in U.S. Pat. No. 5,265,412, seal strips as shown, for example, in U.S. Pat. No. 7,090,224 or labyrinth seals as shown, for example, in U.S. Pat. No. 6,345,494, so as to prevent or limit cool compressed gases from entering into the turbine inlet.